I believe that understanding the sources of noise in digital sensors, and understanding how the noise changes under different conditions, and how the design of the camera might affect both of these things, will significantly increase the success rate when reducing noise in digital images using this calibration method. For that reason I’ve included a section on the theory and engineering considerations that impact these techniques. But if you don’t agree that knowing the theory is useful, you can just skip to the workflow. However, there is a lot that can go wrong during image calibration. Many photographers consider it to be an advanced technique that takes a lot of knowledge and skill to perform successfully. Calibration can fail in a very ugly way when something is done wrong – but it works when you know all the variables that can affect it, and attend to them.